What is a “Process Boss” in machining?

What is a process boss in machining?
JC-tooling master one minute please clarify

The process boss is not a function or structure of the product, but is specially "reserved" for the process. it's an "assist step" 
Process bosses are generally used as rough datums only, and are no longer used when a "fine datum" is machined.
Process boss is out of the process needs, it is not the designer's intention to increase the process boss that the process staff is qualified, is a level. The perpose of the process boss is for precise-locating the item for fabricate, or QC process